zapping gates
John Larkin
300-watt power fets:
IXYS IXTH11P50 p-channel 80 volts
IR IRFPS37N50A n-channel 115 volts
John
Richard Henry
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
news:6fia62135v6i1bier...@4ax.com...
Can you provide more information on test setup and proedure?
John Larkin
wrote:
Well, I connected a power supply between gate and source and turned it
up until the gate blew out... is there another way? Gate was + on the
n-channel fet, - on the p-gadget, which ensured that Vd-s was zero.
So, a failure mode that we thought was possible, isn't. Gotta look
somewhere else.
John
Stanislaw Flatto
> On Fri, 12 May 2006 19:59:39 -0700, "Richard Henry" <rph...@home.com>
> wrote:
>
>
>>"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>news:6fia62135v6i1bier...@4ax.com...
>>
>>>We just tested the gate blowout voltage of a couple of 500-volt,
>>>300-watt power fets:
>>>
>>>IXYS IXTH11P50 p-channel 80 volts
>>>IR IRFPS37N50A n-channel 115 volts
>>
>>Can you provide more information on test setup and proedure?
>>
>
>
> Well, I connected a power supply between gate and source and turned it
> up until the gate blew out...
is there another way?
****************************
YES. It is called "testing" and involves defining what are you testing
and how you control the test parameters so _some_ cosistent info can be
gathered.
Usually you define those things so another tester can repeat your findings.
As reported it is technical gossip;^)
Having fun
Stanislaw
Slack user from Ulladulla.
John Larkin
<com...@shoalhaven.net.au> wrote:
>John Larkin wrote:
>> On Fri, 12 May 2006 19:59:39 -0700, "Richard Henry" <rph...@home.com>
>> wrote:
>>
>>
>>>"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>>news:6fia62135v6i1bier...@4ax.com...
>>>
>>>>We just tested the gate blowout voltage of a couple of 500-volt,
>>>>300-watt power fets:
>>>>
>>>>IXYS IXTH11P50 p-channel 80 volts
>>>>IR IRFPS37N50A n-channel 115 volts
>>>
>>>Can you provide more information on test setup and proedure?
>>>
>>
>>
>> Well, I connected a power supply between gate and source and turned it
>> up until the gate blew out...
>****************************
> is there another way?
>****************************
>
>YES. It is called "testing" and involves defining what are you testing
>and how you control the test parameters so _some_ cosistent info can be
>gathered.
What else would you want to know? The colors of the test leads? What
we had for lunch?
>Usually you define those things so another tester can repeat your findings.
I seriously doubt that the gate breakdown voltage of power fets is
terribly repeatable, and I'm not really interested in testing a couple
hundred $10 fets to destruction and crunching the resulting statistics
to be sure. So if you have any comparable data, I'd love to see it.
I thought it was interesting that both fets died at just about 4x
their rated abs-max gate voltage.
>As reported it is technical gossip;^)
Excuse me, I'm just an engineer.
John
Ian Stirling
> On Sat, 13 May 2006 03:48:05 GMT, Stanislaw Flatto
> <com...@shoalhaven.net.au> wrote:
>
>>John Larkin wrote:
>>> On Fri, 12 May 2006 19:59:39 -0700, "Richard Henry" <rph...@home.com>
>>> wrote:
>>>
>>>
>>>>"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>>>news:6fia62135v6i1bier...@4ax.com...
>>>>
>>>>>We just tested the gate blowout voltage of a couple of 500-volt,
>>>>>300-watt power fets:
>>>>>
>>>>>IXYS IXTH11P50 p-channel 80 volts
>>>>>IR IRFPS37N50A n-channel 115 volts
>>>>
>>>>Can you provide more information on test setup and proedure?
>>>>
>>>
>>>
>>> Well, I connected a power supply between gate and source and turned it
>>> up until the gate blew out...
>>****************************
>> is there another way?
>>****************************
>>
>>YES. It is called "testing" and involves defining what are you testing
>>and how you control the test parameters so _some_ cosistent info can be
>>gathered.
>
>
> What else would you want to know? The colors of the test leads? What
> we had for lunch?
>
>>Usually you define those things so another tester can repeat your findings.
I thought it was interesting that both fets died at just about 4x
> their rated abs-max gate voltage.
>
>>As reported it is technical gossip;^)
>
> Excuse me, I'm just an engineer.
Ramp rate, temperature...
Though I'm deeply ignorant of semiconductor physics, I would expect the
electric field across the junction, and the failure threshold to vary
significantly if it's 1v/s, or 1v/ns.
Stanislaw Flatto
>
>
>>As reported it is technical gossip;^)
>
>
> Excuse me, I'm just an engineer.
>
> John
>
>
>
You are excused.
Now excuse me, but I am just an (electronic) engineer (ret.) with over
25 years in aerospace industry most of them in testing department.
So I read your post and try to make sense of what is written.
Have fun
Jim Thompson
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
[snip]
>
>I thought it was interesting that both fets died at just about 4x
>their rated abs-max gate voltage.
Why is that surprising? The gate oxide is just a
very-carefully-controlled thickness of silicon dioxide (aka glass).
>
>>As reported it is technical gossip;^)
>
>Excuse me, I'm just an engineer.
>
>John
>
>
You are excused ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
John Larkin
<To-Email-Use-Th...@My-Web-Site.com> wrote:
>On Fri, 12 May 2006 21:24:54 -0700, John Larkin
><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>[snip]
>>
>>I thought it was interesting that both fets died at just about 4x
>>their rated abs-max gate voltage.
>
>Why is that surprising? The gate oxide is just a
>very-carefully-controlled thickness of silicon dioxide (aka glass).
>
If it's very-carefully-controlled, why do they guardband it 4:1?
Maybe because it goes down at high drain voltages?
John
John Larkin
wrote:
Rate, as already noted, was a guy turning a knob on a power supply.
And if you read my other posts, I've already suggested the typical
temperatures in San Francisco this time of year.
>Though I'm deeply ignorant of semiconductor physics, I would expect the
>electric field across the junction, and the failure threshold to vary
>significantly if it's 1v/s, or 1v/ns.
1 v/ns is a little fast for my personal wrist. It might be hard to
read the meter at that rate, too.
John
John Larkin
<com...@shoalhaven.net.au> wrote:
>John Larkin wrote:
>
>
>>
>>
>>>As reported it is technical gossip;^)
>>
>>
>> Excuse me, I'm just an engineer.
>>
>> John
>>
>>
>>
>You are excused.
>Now excuse me, but I am just an (electronic) engineer (ret.) with over
>25 years in aerospace industry most of them in testing department.
>So I read your post and try to make sense of what is written.
>
Well, one of us seems to have some doubt about how to measure the gate
breakdown voltage of a mosfet. Interesting.
John
Jim Thompson
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>On Sat, 13 May 2006 07:54:17 -0700, Jim Thompson
><To-Email-Use-Th...@My-Web-Site.com> wrote:
>
>>On Fri, 12 May 2006 21:24:54 -0700, John Larkin
>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>
>>[snip]
>>>
>>>I thought it was interesting that both fets died at just about 4x
>>>their rated abs-max gate voltage.
>>
>>Why is that surprising? The gate oxide is just a
>>very-carefully-controlled thickness of silicon dioxide (aka glass).
>>
>
>If it's very-carefully-controlled, why do they guardband it 4:1?
Hot electrons ;-)
I just checked a process spec... TOX +3%/-5%
>
>Maybe because it goes down at high drain voltages?
>
>John
>
Plus there are some rate effects.
Richard Henry
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>
> Rate, as already noted, was a guy turning a knob on a power supply.
What kind of power supply?
Rene Tschaggelar
> On Sat, 13 May 2006 03:48:05 GMT, Stanislaw Flatto
> <com...@shoalhaven.net.au> wrote:
>
>
>>John Larkin wrote:
>>
>>>On Fri, 12 May 2006 19:59:39 -0700, "Richard Henry" <rph...@home.com>
>>>wrote:
>>>
>>>
>>>
>>>>"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>>>news:6fia62135v6i1bier...@4ax.com...
>>>>
>>>>
>>>>>We just tested the gate blowout voltage of a couple of 500-volt,
>>>>>300-watt power fets:
>>>>>
>>>>>IXYS IXTH11P50 p-channel 80 volts
>>>>>IR IRFPS37N50A n-channel 115 volts
>>>>
>>>>Can you provide more information on test setup and proedure?
>>>>
>>>
>>>
>>>Well, I connected a power supply between gate and source and turned it
>>>up until the gate blew out...
>>
>>****************************
>> is there another way?
>>****************************
>>
>>YES. It is called "testing" and involves defining what are you testing
>>and how you control the test parameters so _some_ cosistent info can be
>>gathered.
>
> What else would you want to know? The colors of the test leads? What
> we had for lunch?
John,
since you ask : the histogram, do a
hundred and plot the histogram.
:-)
Naa. Thanks anyway, I take your measurements
as a hint that the gate voltage could perhaps
survive more than the 15V.
Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
John Larkin
wrote:
>
I think it was grey.
John
Jim Thompson
With vents ?:-)
Richard Henry
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
How noisy was the knob? How steady was the guy turning the knob?
Mac
I don't quite know how this thread went bad. To me, it was a very
interesting post.
Since I've never done anything like this, I was just curious about how one
detects blowout.
Does the current jump up dramatically? Does the part make an audible pop?
I'm sure you had the current limiting set up on the PS, so maybe the
Voltage just drops off suddenly as the current limit kicks in?
--Mac
Ian Stirling
The gate goes from being an essentially perfect insulator (well,
gigohms) to a smallish value resistor, as the stored charge in the gate
region becomes enough to break down the gate dielectric.
The energies are small enough that you won't usually get any audible
sign.
Stanislaw Flatto
a) Destructive or non-destructive test.
b) Proper control of dv/dt and definition what di/dt is defined as
breakdown.
c) Manufacturer definitions of error levels on number(s) given in specs
sheet.
And so on and on.
All this is done so there is "No Entry!" sign for Mr.Murphy and his helpers.
And it IS a branch in our industry, not cheap, but essential.
Have fun
Stanislaw
Slack user in Ulladulla.
John Larkin
<com...@shoalhaven.net.au> wrote:
>>>Now excuse me, but I am just an (electronic) engineer (ret.) with over
>>>25 years in aerospace industry most of them in testing department.
>>>So I read your post and try to make sense of what is written.
>>>
>>
>>
>>
>> Well, one of us seems to have some doubt about how to measure the gate
>> breakdown voltage of a mosfet. Interesting.
>>
>> John
>>
>>
>OK.
>a) Destructive or non-destructive test.
Mosfet gate breakdown? You've got to be kidding.
>b) Proper control of dv/dt and definition what di/dt is defined as
>breakdown.
You *are* kidding, right?
>c) Manufacturer definitions of error levels on number(s) given in specs
>sheet.
Take a look at the datasheets in question; the numbers are in the "abs
max" section. Take a look at their detailed methodology, dv/dt,
definition of breakdown; there ain't any.
>And so on and on.
I get *that* part loud and clear.
>All this is done so there is "No Entry!" sign for Mr.Murphy and his helpers.
I blew up one fet, and I let my customer, who was visiting, blow up
the other one. A good time was had by all, and we immediately
discounted one proposed failure mechanism.
>And it IS a branch in our industry, not cheap, but essential.
We needed data in 5 minutes, and I got it. I'm glad I didn't
commission a team of "testing professionals" to measure these numbers;
they would have needed a budget, a test plan, a test fixture, a test
data sheet, an environmental chamber, a datalogger, an engineer and
three techs, a few meetings, a statistical analysis package, and six
months. And, in my experience, would have connected the fet wrong and
got nonsense data.
>Have fun
Always!
John
Stanislaw Flatto
>
>>OK.
>>a) Destructive or non-destructive test.
>
>
> Mosfet gate breakdown? You've got to be kidding.
Am I? Have you met a component which fails in "one and only" way in all
places of usage?
> Take a look at the datasheets in question; the numbers are in the "abs
> max" section. Take a look at their detailed methodology, dv/dt,
> definition of breakdown; there ain't any.
Must be something special, "new, improved, buy it today!", a gate with
conductors on two sides of insulator which has NO capacitive effects at
any frequency.
> We needed data in 5 minutes, and I got it. I'm glad I didn't
> commission a team of "testing professionals" to measure these numbers;
> they would have needed a budget, a test plan, a test fixture, a test
> data sheet, an environmental chamber, a datalogger, an engineer and
> three techs, a few meetings, a statistical analysis package, and six
> months. And, in my experience, would have connected the fet wrong and
> got nonsense data.
Been there, done it. So is life, what can be done?
>
>
>>Have fun
>
>
> Always!
>
> John
>
legg
Just so long as your test procedure duplicated the environment of the
failure mode being chased, and included a sufficient sample base to
duplicate the rate of failures in evidence.
RL
John Larkin
>On Fri, 12 May 2006 19:56:39 -0700, John Larkin wrote:
>
>> We just tested the gate blowout voltage of a couple of 500-volt,
>> 300-watt power fets:
>>
>> IXYS IXTH11P50 p-channel 80 volts
>> IR IRFPS37N50A n-channel 115 volts
>>
>> John
>
>I don't quite know how this thread went bad. To me, it was a very
>interesting post.
>
>Since I've never done anything like this, I was just curious about how one
>detects blowout.
>
>Does the current jump up dramatically?
Yes. The gate oxide punches through, and then you can push as much
current as the wirebonds can handle.
> Does the part make an audible pop?
No, not unless a huge amount of energy is available, in which case you
get shrapnel. Serious SOA testing *does* make shrapnel.
>I'm sure you had the current limiting set up on the PS, so maybe the
>Voltage just drops off suddenly as the current limit kicks in?
I put a Fluke ammeter in series, but it's not necessary... the gate
shorts the supply, it current limits, and voltage drops to near zero.
I thought the numbers were interesting, and thought others might have
data on other parts. I didn't expect to get ragged over methodology,
especially from a bunch of people who sound like armchair engineers.
John
Richard Henry
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
I admit I am sitting in my armchair. I don't see why asking for more data
should be offensive.
John Larkin
wrote:
>
Not offensive, just very, very silly. I mean, I told everybody exactly
what I did, like turning the pot on the power supply and reading the
meter, and then people ask me stuff like what kind of supply I used,
and how many volts/ns were applied.
Nobody has, of course, presented *any* other data. That would require
actual interest or actual activity. In the "led as photodector"
thread, a few people actually got off their butts and produced some
numbers.
John
Richard Henry
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
If I were to try to produce some other numbers, I would try to imitate as
closely as possible your test setup and method. Thus the questions.
Also, if I were to get different numbers, I would look for differences
intest setup or method as the first step to resolving the differences.
Genome
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
> We just tested the gate blowout voltage of a couple of 500-volt,
> 300-watt power fets:
>
> IXYS IXTH11P50 p-channel 80 volts
> IR IRFPS37N50A n-channel 115 volts
>
> John
>
You might have had some mong over this but you are being a bit 'stupid'.
Simple answer is manufacturers 'characterise' on the basis of their
processes.
Your absolute maximum gate voltage might be +/-20V. As a result Mr
manufacturer might be able to shove 100% of product through the gate........
without testing. Even then he will probably also accept some statistical sum
of failures as long as they are acceptable.
Of course, you.... as 'Mr stupid'.... might have some failure mode you are
thinking about. Let's say there is a possibility that your circuit, for some
reason might overvoltage the gate.
You get two choices.
Either sort out your gate drive circuit so it will not overvoltage the gate.
or
'Qualify' the mosfets you buy from the manufacturer and use in your product
to demonstrate that the ones that you 'select' will be reliable in the
intended application.
You appear to have used choice three, which does not exist.
Call the (thick) customer in and demonstrate how two mosfets will work in
the circuit you have designed.
Obviously, since the contract is worth $50,000, there is absolutely no way
you would have burned up $500 worth of mosfets to find the two that would
work in your circuit with the percieved failure mode.
DNA
Spehro Pefhany
Without going back and re-reading the beginning of the thread, it
sounded more like he had a small number of unexplained failures on an
existing product and trying to rule out or rule in gate overvoltage as
a possible cause. Checking the 'typical' failure voltage is a
perfectly valid approach under those conditions, no?
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Joerg
>
> We needed data in 5 minutes, and I got it. I'm glad I didn't
> commission a team of "testing professionals" to measure these numbers;
> they would have needed a budget, a test plan, a test fixture, a test
> data sheet, an environmental chamber, a datalogger, an engineer and
> three techs, a few meetings, a statistical analysis package, and six
> months. And, in my experience, would have connected the fet wrong and
> got nonsense data.
>
"the fet"? It would have to be "the fets" and probably a few hundred
times x different batch numbers. To the tune of $10 each or so. It'll
only be an additional $50k, or maybe $100k, nothing compared to the guy
who had his Lamborghini nailed to the wall (did you read that one?).
Anyway, thank for sharing. Wouldn't have thought a FET could stomach
four times abs max. Wow.
Regards, Joerg
Genome
"Spehro Pefhany" <spef...@interlogDOTyou.knowwhat> wrote in message
news:328f62hd1blkf6njl...@4ax.com...
Err, no... don't bend my head... go back and read the whole.
Perhaps John was just testing.
DNA
Mac
[snip]
> I thought the numbers were interesting, and thought others might have
> data on other parts. I didn't expect to get ragged over methodology,
> especially from a bunch of people who sound like armchair engineers.
>
Amen. Let them go frag their own FET's. ;-)
> John
--Mac
John Larkin
wrote:
>Call the (thick) customer in and demonstrate how two mosfets will work in
>the circuit you have designed.
>
>Obviously, since the contract is worth $50,000,
About $900,000 so far, and sales are picking up.
John
Genome
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
Hmmm.... you appear to have a locked creativity problem.
Look for other avenues. (I have no suggestions.... other than a hairy single
seater flying thing)
DNA
Fritz Schlunder
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
> We just tested the gate blowout voltage of a couple of 500-volt,
> 300-watt power fets:
>
> IXYS IXTH11P50 p-channel 80 volts
> IR IRFPS37N50A n-channel 115 volts
>
> John
For those who are interested in this topic, it may be of value to read this
document:
http://www.irf.com/technical-info/appnotes/an-986.pdf
In particular section III. "Experimental verification" under the
observations 1. and 3. will be of interest. Basically they claim standard
gate MOSFETs typically are destroyed around 70-80V, with logic level devices
around 45V-50V. Additionally, if gate avalanche currents are limited to a
very small level (IE: <100uA) the gates don't seem to be immediately
destroyed. I've seen this basic data also claimed in at least one other
document from International Rectifier, but unfortunately I can't remember
exactly what document that was in.
John's IRFPS37N50A 115V figure is entirely believable and probably not at
all unusual for MOSFETs with datasheet absolute maximum gate ratings of
+/-30V. For absolute maximum rated +/-20V devices, I would expect 80V
breakdown to be more typical.
Manufacturers benefit in more than one way by producing datasheets with very
conservative maximum gate voltage ratings. In particular, devices will
still be more reliable at lower gate voltage (especially over the long run),
and it will help to improve product yield. For example, if during the
manufacturing process a tiny fleck of dust were to land on a MOSFET while
the gate oxide is being grown, it would no doubt introduce a gate oxide
imperfection that would reduce the gate breakdown voltage (though not
necessarily enough to make the device useless). For example, suppose the
imperfection reduces the breakdown voltage from 80V down to 40V. The device
can still be sold if the datasheet specifies 20V abs. max voltage, but it
could not be sold if the datasheet specified 60V absolute max.
Additionally, there is essentially no benefit (in terms of on resistance or
maximum current handling ability) for driving MOSFET gates beyond 20V, or
even 15V for that matter, for typical MOSFETs (there are some that still
benefit a little, but most don't). For the most part the on resistance and
maximum current capability with Vgs at 10V is essentially very nearly as
good as it will get regardless of how high a voltage you apply.
Mike Monett
news:e48kmp$h0g$1...@emma.aioe.org:
> For those who are interested in this topic, it may be of value to read
> this document:
>
> http://www.irf.com/technical-info/appnotes/an-986.pdf
Interesting - Thanks for posting this info.
How do you get the figures to show? I tried Acrobat 5.0 and Foxit, and
neither showed any images. The pdf header says it is "PDF-1.3", which
I believe means it is version 4.0 so any viewer should work fine.
What's the trick?
Regards,
Mike Monett
Spehro Pefhany
I don't think they're in there.
Terry Given
there will be a gaussian distribution hiding in there too.
back when my employer used to give Hitachi AIC $1,500,000 per year, we
got ALL of the factory data. spec'd lifetime is -3 standard deviations;
mean lifetime was 2x rated lifetime.
Cheers
Terry
Mike Monett
>>What's the trick?
>>
>>Regards,
>>
>>Mike Monett
> I don't think they're in there.
> Best regards,
> Spehro Pefhany
I didn't think so either, but ya gotta be careful making hard and fast
statements with this bunch. Someone (usually with the initials S.P.) will
often post a reply to the effect you need to click on a hidden icon in the
upper right corner, which opens a new menu, and so forth.
So I tend to weasel-word my posts as much as possible:)
Regards,
Mike Monett
Mike Monett
> I blew up one fet, and I let my customer, who was visiting, blow up
> the other one. A good time was had by all, and we immediately
> discounted one proposed failure mechanism.
So can you give us more info on the failure and any idea what caused the
problem? Maybe ESD during handling? I understand this can cause a latent
defect that fails later in service.
Regards,
Mike Monett
Stanislaw Flatto
> I thought the numbers were interesting, and thought others might have
> data on other parts. I didn't expect to get ragged over methodology,
> especially from a bunch of people who sound like armchair engineers.
I like your musical expertise.
OK. How about "armchair" in "Fouga Magister" (no parashute, "We don't
need it at 6 meters above water" - the test pilot declaration) with the
Honeywell UV recorder on my knees, to do some "armchair" testing at
600km/h.
>
> John
>
>
Stanislaw
Slack user from Ulladulla.
Fred Bartoli
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> a écrit dans le
message de news:bgue62525d25j6c6l...@4ax.com...
Hey, they forgot to ask what was the total RMS noise and its PSD, if it
changed with the applied voltage, what was the leads inductance, the
coupling factor between the D-S and G-S loops and also how many neutrinos
crossed the die during the experiment.
That's the way I'd define the experiment conditions, plus some others I sure
forget.
Not very serious testing engineers, aren't they?
--
Thanks,
Fred.
John Larkin
Yup, that's about what's going on. The gadgets never fail here, in
test/burnin, but sometimes they fail in the field. We're performing
all sorts of abuse here, but no failures so far... low-rate failures
are hard to pin down.
During the investigation, we have found two bugs in the customer's
system that drives our box but, alas, I can't honestly blame the
failures on them.
I like to test parts to failure and remember the numbers, like my 0603
resistor that failed at 1600 volts.
John
John Larkin
wrote:
Ah, the John Denver solution.
John
dalai lamah
> IR IRFPS37N50A n-channel 115 volts
Since this thread has gone a little polemic, please don't misunderstand me
when I ask you (with all the good intentions): what were you trying to
prove? If datasheet says Vgsmax is 30 V, I think it's safe to stay under
30V, no matter how conservative are the absolute ratings. What good will
make (in general and in your specific case) to know that a single model
withstood 115 V?
--
asd
John Larkin
wrote:
Interesting; thanks for the link. It's a pretty wordy paper, but the
conclusion...
VI. Conclusions
The use of a capacitive discharge into the gate to identify ESD
sensitivity of a MOS-gated transistor does not seem to
provide any additional information beyond what can be obtained more
accurately from a curve tracer and simple
calculations.
It is recommended that, for MOS-gated power transistors, the ESD test
circuits shown in Figure 2 be replaced by a
simple dielectric strength test performed with a curve tracer,
completed by simple calculations, as per Figure 3.
implies that rate effects aren't important.
There's no date on the paper, but they do refer to a "memoscope."
John
Jim Thompson
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
[snip]
>
>VI. Conclusions
>The use of a capacitive discharge into the gate to identify ESD
>sensitivity of a MOS-gated transistor does not seem to
>provide any additional information beyond what can be obtained more
>accurately from a curve tracer and simple
>calculations.
>It is recommended that, for MOS-gated power transistors, the ESD test
>circuits shown in Figure 2 be replaced by a
>simple dielectric strength test performed with a curve tracer,
>completed by simple calculations, as per Figure 3.
>
>
>implies that rate effects aren't important.
>
>There's no date on the paper, but they do refer to a "memoscope."
>
>John
Except that the actual failure mechanism is most likely metal
migration through "pin holes" in the oxide. "Rate" will cause hot
spots and thus affect the failure mechanism.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Genome
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
That's a bit above my head.
Wasn't he the bloke who played guitar, sang irritating songs with shit
lyrics and wore glasses? Not Roy Orbisson..... the other one.
How did these people manage to define the intelligence of the American
Nation?
Anyway $900,000 can't be too far from a second hand single military type jet
thingy. Get one with two to give the wife a bit of pleasure and put the
shits up the employees....
Is John Denver dead? Should I assume he buried his plane with himself in it?
Can I assume that you will not make the same mistakes?
DNA
John Larkin
wrote:
>>
>> Ah, the John Denver solution.
>>
>> John
>>
>
>That's a bit above my head.
>
>Wasn't he the bloke who played guitar, sang irritating songs with shit
>lyrics and wore glasses? Not Roy Orbisson..... the other one.
Roy ain't that bad. JD did "Rocky Mountain High" and "Country Road"
and some really repulsive love songs. He was weirder than Roy, in his
own way.
>
>How did these people manage to define the intelligence of the American
>Nation?
I once was deeply in love with a wonderful, beautiful woman until I
discovered that she had the complete collection of Barry Manilow
records.
>Is John Denver dead? Should I assume he buried his plane with himself in it?
>Can I assume that you will not make the same mistakes?
>
He took an ultralight out over the ocean, in southern California, and
apparently forgot to do the pre-flight checks, especially as regards
gas. I think flying a small plane is about as exciting as driving a
truck, although I might like to try sailplane aerobatics some day. If
I go violently, I'd prefer to ski off a cliff.
There was a teevee show on last week, about an Airbus 330 that ran out
of gas over the Atlantic, lost all power, turned around, glided for 20
minutes, and managed to land on a military airstrip in the Azores.
Impressive. I thought these things glided about as well as cinder
blocks.
John
Jim Thompson
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
[snip]
>
>There was a teevee show on last week, about an Airbus 330 that ran out
>of gas over the Atlantic, lost all power, turned around, glided for 20
>minutes, and managed to land on a military airstrip in the Azores.
>Impressive. I thought these things glided about as well as cinder
>blocks.
>
>
>John
>
IIRC late '50's, early '60's. Some air transport company plane, 707,
ran out of fuel and sat down on Ohio State Route 7 (parallels the Ohio
River). Did just fine until they came to an overpass ;-) Stripped
the wings right off. Fortunately no fuel.
Joerg
>
> There was a teevee show on last week, about an Airbus 330 that ran out
> of gas over the Atlantic, lost all power, turned around, glided for 20
> minutes, and managed to land on a military airstrip in the Azores.
> Impressive. I thought these things glided about as well as cinder
> blocks.
>
The big iron isn't as bad as their size makes them appear to be. Once I
was on a 767 flight and about an hour shy of the Belgian coast an engine
quit. This meant there was only one engine left which luckily kept
humming. The pilots were able to bring it into Frankfurt/Germany on a
long stretch (but all the airspace was cleared and there were dozens of
fire trucks waiting...). The plane was yawing pretty badly but we made
it. Must have been a white-knuckle event for the pilots since they
really had to nail that landing well.
Regards, Joerg
Richard Henry
"Joerg" <notthis...@removethispacbell.net> wrote in message
news:Jp6ag.76929$H71....@newssvr13.news.prodigy.com...
Two-engine commercial planes that cannot function properly on one engine
should be banned.
Fred
"Richard Henry" <rph...@home.com> wrote in message
news:60s9g.1587$KB.727@fed1read08...
>
> "John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in
> message
>> On Sat, 13 May 2006 10:18:47 -0700, "Richard Henry" <rph...@home.com>
>> wrote:
>>
>> >
>> >"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in
> message
>> >>
>> >> Rate, as already noted, was a guy turning a knob on a power supply.
>> >
>> >What kind of power supply?
>> >
>>
>> I think it was grey.
>
> How noisy was the knob? How steady was the guy turning the knob?
>
>
Approximately this noisy and that steady. :-P
Joerg
>>
>>The big iron isn't as bad as their size makes them appear to be. Once I
>>was on a 767 flight and about an hour shy of the Belgian coast an engine
>>quit. This meant there was only one engine left which luckily kept
>>humming. The pilots were able to bring it into Frankfurt/Germany on a
>>long stretch (but all the airspace was cleared and there were dozens of
>>fire trucks waiting...). The plane was yawing pretty badly but we made
>>it. Must have been a white-knuckle event for the pilots since they
>>really had to nail that landing well.
>
> Two-engine commercial planes that cannot function properly on one engine
> should be banned.
>
The 767 certainly could function. But I guess they didn't know why the
first engine quit and were worried that the other one might as well.
Fuel contamination or whatever.
Regards, Joerg
Stanislaw Flatto
>
> There's no date on the paper, but they do refer to a "memoscope."
>
> John
>
This instrument preceded MOS-FET's few years I used a Tektronix and HP
ones in early '60.
Tim Williams
> Two-engine commercial planes that cannot function properly on one engine
> should be banned.
AFAIK, they are rated to fly with just one engine. Two are there for
reliability, not having to trim the rudder like hell, and of course higher
performance.
Tim
--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Keith
jjla...@highNOTlandTHIStechnologyPART.com says...
> On Mon, 15 May 2006 18:33:30 GMT, "Genome" <ilike...@yahoo.co.uk>
> wrote:
>
> >>
> >> Ah, the John Denver solution.
> >>
> >> John
> >>
> >
> >That's a bit above my head.
> >
> >Wasn't he the bloke who played guitar, sang irritating songs with shit
> >lyrics and wore glasses? Not Roy Orbisson..... the other one.
>
> Roy ain't that bad. JD did "Rocky Mountain High" and "Country Road"
> and some really repulsive love songs. He was weirder than Roy, in his
> own way.
>
> >
> >How did these people manage to define the intelligence of the American
> >Nation?
>
> I once was deeply in love with a wonderful, beautiful woman until I
> discovered that she had the complete collection of Barry Manilow
> records.
>
>
> >Is John Denver dead? Should I assume he buried his plane with himself in it?
> >Can I assume that you will not make the same mistakes?
> >
>
> He took an ultralight out over the ocean, in southern California, and
> apparently forgot to do the pre-flight checks, especially as regards
> gas.
Yes, but not an ultralight, a "home-built" Rutan Long-EZ[*]. JD
was known to be a dangerous pilot.
[*] http://en.wikipedia.org/wiki/Long-EZ
> I think flying a small plane is about as exciting as driving a
> truck, although I might like to try sailplane aerobatics some day. If
> I go violently, I'd prefer to ski off a cliff.
>
> There was a teevee show on last week, about an Airbus 330 that ran out
> of gas over the Atlantic, lost all power, turned around, glided for 20
> minutes, and managed to land on a military airstrip in the Azores.
> Impressive. I thought these things glided about as well as cinder
> blocks.
Commercial jets can do a 10:1 glide ratio, at least. If they're
30k ft (6 miles) up... The amazing thing is that they had power to
get the thing down.
--
Keith
John Larkin
>>
>> There was a teevee show on last week, about an Airbus 330 that ran out
>> of gas over the Atlantic, lost all power, turned around, glided for 20
>> minutes, and managed to land on a military airstrip in the Azores.
>> Impressive. I thought these things glided about as well as cinder
>> blocks.
>
>Commercial jets can do a 10:1 glide ratio, at least. If they're
>30k ft (6 miles) up... The amazing thing is that they had power to
>get the thing down.
Yeah. The rate of descent must have been roughly 1000 fpm, as they
arrived at the island at about 10,000 feet. They circled a bit and
came in at 250 mph...no flaps! Good thing it's a 2-mile military
runway, one of the Shuttle backup strips. The gear caught fire but of
course there was no fuel to burn.
One of my customers, the Hamilton-Sundstrand div of United
Technologies, makes aircraft power systems. They make "the thing you
never want to see used", a little propeller-powered generator. When
all else is dead, as on the A330, the pilot pulls a lever, a hatch
opens, and this thing drops into the airstream.
It does surprise me the the same fuel supply is apparently used for
the main engines and for the APU.
John
Pooh Bear
John Larkin wrote:
Canadian airlines have a history of gliding airliners ( the A330 in this case
was operated by Air Transat ). In 1983 an Air Canada Boeing 767 ran out of fuel
enroute and also managed to glide succesfully to a suitable runway.
http://en.wikipedia.org/wiki/Gimli_Glider
The two aircraft are apparently known unofficially to aircrew as the Gimli
Glider and the Azores Glider.
> It does surprise me the the same fuel supply is apparently used for
> the main engines and for the APU.
You'd hate to have some APU fuel left should the main engines flame out.
Graham
Robert Latest
John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote
in Msg. <81rj62dh911rjbrkr...@4ax.com>
> Technologies, makes aircraft power systems. They make "the thing you
> never want to see used", a little propeller-powered generator. When
> all else is dead, as on the A330, the pilot pulls a lever, a hatch
> opens, and this thing drops into the airstream.
Is that a standard thing on commercial aircraft?
robert
Jim Thompson
Plus it goes "stale" and gets jelly-like.
John Larkin
Keith
jjla...@highNOTlandTHIStechnologyPART.com says...
THay have to have some sort of APU, above a certain size. Smaller
planes (727/737/MD80 class) are still small enough for the pilot to
moose the controls around. Large aircraft need hydraulic assist so
there has to be some APU for engines-out. I believe some
commercial craft have a JP4 driven emergency power unit in the
tail. Military jets (e.g. F16) often use hydrazine in their APUs.
...nasty stuff though.
--
Keith
Spehro Pefhany
I suppose they must test them regularly.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
ehsjr
> On Mon, 15 May 2006 14:12:07 -0700, John Larkin
> <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
> [snip]
>
>>There was a teevee show on last week, about an Airbus 330 that ran out
>>of gas over the Atlantic, lost all power, turned around, glided for 20
>>minutes, and managed to land on a military airstrip in the Azores.
>>Impressive. I thought these things glided about as well as cinder
>>blocks.
>>
>>
>>John
>>
>
>
> IIRC late '50's, early '60's. Some air transport company plane, 707,
> ran out of fuel and sat down on Ohio State Route 7 (parallels the Ohio
> River). Did just fine until they came to an overpass ;-) Stripped
> the wings right off. Fortunately no fuel.
>
> ...Jim Thompson
Nowadays someone would sue the construction company
for not making the overpass wide enough. I'm not a
pilot - I don't even play one on TV - but landing a
707 on a highway sounds like some pretty impressive
flying to me.
Ed
John Larkin
<spef...@interlogDOTyou.knowwhat> wrote:
>On Tue, 16 May 2006 11:16:50 -0700, the renowned John Larkin
><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>>On 16 May 2006 16:03:54 GMT, Robert Latest <bobl...@yahoo.com>
>>wrote:
>>
>>>On Tue, 16 May 2006 08:28:10 -0700,
>>> John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote
>>> in Msg. <81rj62dh911rjbrkr...@4ax.com>
>>>
>>>> Technologies, makes aircraft power systems. They make "the thing you
>>>> never want to see used", a little propeller-powered generator. When
>>>> all else is dead, as on the A330, the pilot pulls a lever, a hatch
>>>> opens, and this thing drops into the airstream.
>>>
>>>Is that a standard thing on commercial aircraft?
>>
>>I think so.
>>
>>John
>
>I suppose they must test them regularly.
>
>
>Best regards,
>Spehro Pefhany
Here it is...
http://www.hamiltonsundstrandcorp.com/hsc/proddesc_display/0,10401,CLI1_DIV22_ETI2937_PRD30,00.html
John
Jim Thompson
wrote:
Even back then it was 4-lane divided.
Joerg
>>Two-engine commercial planes that cannot function properly on one engine
>>should be banned.
>
> AFAIK, they are rated to fly with just one engine. Two are there for
> reliability, not having to trim the rudder like hell, and of course higher
> performance.
>
Fly, yes, but not at high altitudes. The 767 where one quit was
descending quite a bit when that happened. At first they said it's a
weather related change but looking out the windows most of us said
"yeah, right". The yaw was quite noticeable and minutes later the
captain told us what really happened. Then I understood why they used
that little white lie, several seasoned biz travelers had panic in their
eyes and buried their fingers into the arm rests as if trying to hold on.
Regards, Joerg
Rich Grise
> On Mon, 15 May 2006 14:12:07 -0700, John Larkin
>>
>>There was a teevee show on last week, about an Airbus 330 that ran out
>>of gas over the Atlantic, lost all power, turned around, glided for 20
>>minutes, and managed to land on a military airstrip in the Azores.
>>Impressive. I thought these things glided about as well as cinder
>>blocks.
>
> ran out of fuel and sat down on Ohio State Route 7 (parallels the Ohio
> River). Did just fine until they came to an overpass ;-) Stripped
> the wings right off. Fortunately no fuel.
The 707 is an amazingly robust airplane - "They don't make them like
they used to" - and the only really hard part about landing a big airplane
like that is getting used to the ground effects when you flare - you think
you're just going to settle to the runway, but suddenly find that you're
floating over it, and going to go off the end, so you have to drive the
plane into the ground, kinda.
Cheers!
Rich
John Larkin
wrote:
http://www.aviationexplorer.com/707_roll_video.htm
John
Rich Grise
> On Wed, 17 May 2006 21:00:54 GMT, Rich Grise <rich...@example.net>
>>> On Mon, 15 May 2006 14:12:07 -0700, John Larkin
>>> [snip]
>>>>
>>>>There was a teevee show on last week, about an Airbus 330 that ran out
>>>>of gas over the Atlantic, lost all power, turned around, glided for 20
>>>>minutes, and managed to land on a military airstrip in the Azores.
>>>>Impressive. I thought these things glided about as well as cinder
>>>>blocks.
>>>
>>> IIRC late '50's, early '60's. Some air transport company plane, 707,
>>> ran out of fuel and sat down on Ohio State Route 7 (parallels the Ohio
>>> River). Did just fine until they came to an overpass ;-) Stripped
>>> the wings right off. Fortunately no fuel.
>>
>>The 707 is an amazingly robust airplane - "They don't make them like
>>they used to" - and the only really hard part about landing a big airplane
>>like that is getting used to the ground effects when you flare - you think
>>you're just going to settle to the runway, but suddenly find that you're
>>floating over it, and going to go off the end, so you have to drive the
>>plane into the ground, kinda.
>
Way kewl! Can't do it in a B-52, at least not at 300 feet:
http://www.alexisparkinn.com/photogallery/Videos/B-52%20Crash.mpg
It's the fourth one down here, in case that link doesn't work:
http://www.rapp.org/archives/2004/09/aircraft_crash_videos/
Cheers!
Rich
John Larkin
wrote:
Way creepy.
Do you remember PSA? They used to run shuttle flights between LAX and
SFO every hour. You'd go the the airport, go to the waiting area, and
get on the next plane. No tickets, no ID, no security, you just paid
the $15 on board in cash. I did it a bunch when I was consulting for
UCLA.
Anyhow the story I was told, maybe an U.L., was that the pilots were
bored one night flying a 727 from LAX up the coast, so they started
doing rolls for fun. They did four, I think, until a stewardess looked
out the window and saw the world upside down and freaked and turned
them in. The pilots were fired, according to the story.
John
Rich Grise
> On Thu, 18 May 2006 18:17:50 GMT, Rich Grise <rich...@example.net>
>>> On Wed, 17 May 2006 21:00:54 GMT, Rich Grise <rich...@example.net>
>>>>The 707 is an amazingly robust airplane - "They don't make them like
>>>>they used to" - and the only really hard part about landing a big airplane
>>>>like that is getting used to the ground effects when you flare - you think
>>>>you're just going to settle to the runway, but suddenly find that you're
>>>>floating over it, and going to go off the end, so you have to drive the
>>>>plane into the ground, kinda.
>>>
>>> http://www.aviationexplorer.com/707_roll_video.htm
>>
>>Way kewl! Can't do it in a B-52, at least not at 300 feet:
>>http://www.alexisparkinn.com/photogallery/Videos/B-52%20Crash.mpg
>>It's the fourth one down here, in case that link doesn't work:
>>http://www.rapp.org/archives/2004/09/aircraft_crash_videos/
>
> Way creepy.
>
I originally saw the whole video, with commentary, where the pilot was
some kind of loose cannon hot-shot, and had been explicitly forbidden
from trying to do aerobatics in a BUF (Big Ugly Fucker), but he thought,
"Hell, I'm invulnerable!", like most college grads do. In the version of
that video that I saw, you can see two ejection seats leave the airplane
just before it goes in - I think a couple of the guys survived - did you
know that some of the seats in the B-52 actually eject _downward_?
> Do you remember PSA? They used to run shuttle flights between LAX and
> SFO every hour. You'd go the the airport, go to the waiting area, and
> get on the next plane. No tickets, no ID, no security, you just paid the
> $15 on board in cash. I did it a bunch when I was consulting for UCLA.
Never been that close to the turf, but I have taken ridiculously
inexpensive commuter flights - one time, from SFO to Oakland, we were
on ascent for about 5 minutes, and descent for another 5, and we were
on the ground. Possiblly surprisingly, it was quicker and cheaper than
a taxicab! :-)
>
> Anyhow the story I was told, maybe an U.L., was that the pilots were
> bored one night flying a 727 from LAX up the coast, so they started
> doing rolls for fun. They did four, I think, until a stewardess looked
> out the window and saw the world upside down and freaked and turned them
> in. The pilots were fired, according to the story.
I should go see "Apollo 13", the Ron Howard movie - one time on some
talk show, he was whining that on the Vomit Comet, whoever wasn't in a
particular zero-gee scene would be in the back of the plane playing
Superman, and he was stuck working!
Closest I've ever been to zero-gee was "free-fall", which isn't really;
Air is surprisingly viscous when you're going straight down from 10,000
feet with nothing but you, God, and a rip cord. ;-)
(there I was, at twelve five, with nothing but a silkworm and a sewing
machine....) ;-)
Cheers!
Rich
Keith
jjla...@highNOTlandTHIStechnologyPART.com says...
It was a 1G roll so the gravity vector was always in the same
orientation WRT the aircraft. The aircraft nor anything inside
knew it was upside down...
>
> Do you remember PSA? They used to run shuttle flights between LAX and
> SFO every hour. You'd go the the airport, go to the waiting area, and
> get on the next plane. No tickets, no ID, no security, you just paid
> the $15 on board in cash. I did it a bunch when I was consulting for
> UCLA.
>
> Anyhow the story I was told, maybe an U.L., was that the pilots were
> bored one night flying a 727 from LAX up the coast, so they started
> doing rolls for fun. They did four, I think, until a stewardess looked
> out the window and saw the world upside down and freaked and turned
> them in. The pilots were fired, according to the story.
...unless one looked out the window. ;-)
--
Keith
Greg Neff
wrote:
<snip>
>Closest I've ever been to zero-gee was "free-fall", which isn't really;
>Air is surprisingly viscous when you're going straight down from 10,000
>feet with nothing but you, God, and a rip cord. ;-)
>
>(there I was, at twelve five, with nothing but a silkworm and a sewing
>machine....) ;-)
>
>Cheers!
>Rich
I experienced zero-gee once on an Air Canada flight on approach to
Philadelphia. It lasted for about three seconds, followed by a
similar period at about two-gees. I remember watching a surprised
flight attendant in the aisle quickly brace herself. I was impressed
that she managed to stay on her feet. After we landed and parked at
the gate, the captain got on the PA and explained that the maneuver
was necessary to avoid another aircraft.
================================
Greg Neff
VP Engineering
*Microsym* Computers Inc.
gr...@guesswhichwordgoeshere.com
Paul Hovnanian P.E.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
In the force if Yoda's so strong, construct a sentence with words in
the proper order then why can't he?
John Larkin
<antoni...@hotmail.com> wrote:
>Un bel giorno John Larkin digitò:
>
>> IR IRFPS37N50A n-channel 115 volts
>
>Since this thread has gone a little polemic, please don't misunderstand me
>when I ask you (with all the good intentions): what were you trying to
>prove?
Prove? I just thought the numbers were interesting. The gate leakage
numbers are cool, too. Who needs a reason?
>If datasheet says Vgsmax is 30 V, I think it's safe to stay under
>30V, no matter how conservative are the absolute ratings.
Gosh.
John
Harry Dellamano
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
news:q9j972hhta0pagk5b...@4ax.com...
without defending it to the n'th degree. What a PITA. It was interesting to
see who gave you a lot of sh*t and who took it at face value. These people
do not realize that there is a gray zone between Absolute Maximum and
Absolute Failure. You reported Absolute Failure which is needed info.
MOSFETs may not fail if you exceed the AM. I will remember your data point
the next time I smoke a MOSFET and must determine exactly what caused the
failure. In catastrophic situations, many strange things happen and this may
help to solve the puzzle.
I remember and found it very informative, your reporting MOSFET performance
to >200c. Interesting that you did not receive much grief for that report.
It has be helpful to me in diagnosing some catastrophic failures.
I hope that this does not deter you from reporting useful information in
the future. Maybe you should distribute it as "data taken because I could".
Regards,
Harry
Terry Given
ditto. interesting.
of course it does make me wonder about the absolute failure dynamic gate
voltage (c.f. DC). I think I can make a hand-wavy argument that it will
be lower, and related to Tr, Tf. Alas, I do not have a 20-80V pulse
generator with adjustable slope, or I'd give it a whiz.
the ESD testing would account for this, as its a charge transfer thing
that happens pretty quickly. Hey, thats how to test it - charge up a
cap, then smack it across the gate with a low Rdson FET. peak current
very high, FET controls it and slope, and any old LV pulse gen will do.
I'll give it a crack this arvo.
Cheers
Terry
John Larkin
wrote:
For a *really* fast hv edge, use a relay.
John
Jim Thompson
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
[snip]
>
>For a *really* fast hv edge, use a relay.
>
>John
>
Mercury-wetted. I used to make fast edge, short-width pulses by
driving a shorted-termination transmission line with a mercury-wetted
relay.
Terry Given
> On Thu, 25 May 2006 18:04:10 -0700, John Larkin
> <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
> [snip]
>
>>For a *really* fast hv edge, use a relay.
>>
>>John
>>
>
>
> Mercury-wetted. I used to make fast edge, short-width pulses by
> driving a shorted-termination transmission line with a mercury-wetted
> relay.
>
> ...Jim Thompson
Noted, thanks guys.
with 1uF of capacitance, a 47N60S5 switching fet and an IRFBC40 DUT,
with a Tektronix AFG310 signal generator, it happily ate 30 or so 60-V
gate pulses. A single 90V pulse wrecked it. The edges are a bit slow,
90V in 250ns, but thats cos I've got Rg = 50.
So: if the dynamic abs-fail voltage is lower than Johns measured 80V,
its not by much. I've run out of FETs I want to break (that was a
left-over lying on the bench).
Cheers
Terry
dalai lamah
> Prove? I just thought the numbers were interesting. The gate leakage
> numbers are cool, too. Who needs a reason?
The numbers are interesting indeed, and you don't have to give any reason,
with "prove" I meant "prove to yourself". My english has its limitations,
please be patient. :)
I was meaning: why did you take the time to pick some MOSFET and zap them?
Were you just curious or did you think this information will be useful for
you sometimes?
>>If datasheet says Vgsmax is 30 V, I think it's safe to stay under
>>30V, no matter how conservative are the absolute ratings.
>
> Gosh.
Are you saying that if you will use that component for a serious design,
you are going to do one or more of the above?
1) Willfully use Vgses >30V
2) Not put any protection circuit to avoid Vgses>30V, because "if I'm
lucky, it's going to withstand at least 100V"
3) Choosing this MOSFET instead of another, because "in the single test
I've made, it withstood a greater voltage than the other"
--
asd
dalai lamah
> Darn! I thought this was going to be another anti Microsoft rant.
What?
--
asd
John Larkin
<antoni...@hotmail.com> wrote:
>Un bel giorno John Larkin digitò:
>
>> Prove? I just thought the numbers were interesting. The gate leakage
>> numbers are cool, too. Who needs a reason?
>
>The numbers are interesting indeed, and you don't have to give any reason,
>with "prove" I meant "prove to yourself". My english has its limitations,
>please be patient. :)
No, your English is fine.
We're having one of our products, a 17 KW peak power MRI gradient
driver, blow up in the field now and then, so we were investigating
failure mechanisms. It doesn't look like even severe drain dv/dt
transients can couple into the gate enough to damage the fets, so that
ain't it.
John